/*
 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*-
 * Copyright (c) 1988 University of Utah.
 * Copyright (c) 1982, 1986, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department, and code derived from software contributed to
 * Berkeley by William Jolitz.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * from: Utah $Hdr: mem.c 1.13 89/10/08$
 *	@(#)mem.c	8.1 (Berkeley) 6/11/93
 */

#include <mach_load.h>

/*
 * Memory special file
 */

#include <sys/param.h>
#include <sys/dir.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/vm.h>
#include <sys/uio_internal.h>
#include <sys/malloc.h>

#include <mach/vm_types.h>
#include <mach/vm_param.h>
#include <vm/vm_kern.h>         /* for kernel_map */

extern addr64_t kvtophys(vm_offset_t va);
extern boolean_t kernacc(off_t, size_t);
#if !defined(SECURE_KERNEL)
extern int setup_kmem;
#endif

static caddr_t devzerobuf;

int mmread(dev_t dev, struct uio *uio);
int mmwrite(dev_t dev, struct uio *uio);
int mmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p);
int mmrw(dev_t dev, struct uio *uio, enum uio_rw rw);

int mmread(dev_t dev, struct uio *uio)
{

    return (mmrw(dev, uio, UIO_READ));
}

int mmwrite(dev_t dev, struct uio *uio)
{

    return (mmrw(dev, uio, UIO_WRITE));
}

int mmioctl(dev_t dev, u_long cmd, __unused caddr_t data, __unused int flag, __unused struct proc *p)
{
    int minnum = minor(dev);

    if (0 == minnum || 1 == minnum) {
        /*
         * /dev/mem and /dev/kmem 
         */
#if defined(SECURE_KERNEL)
        return (ENODEV);
#else
        if (0 == setup_kmem)
            return (EINVAL);
#endif
    }

    switch (cmd) {
    case FIONBIO:
    case FIOASYNC:
        /*
         * OK to do nothing: we always return immediately 
         */
        break;
    default:
        return ENODEV;
    }

    return (0);
}

int mmrw(dev_t dev, struct uio *uio, enum uio_rw rw)
{
    register int o;
    register u_int c, v;
    int error = 0;
    vm_offset_t where;
    vm_size_t size;

    while (uio_resid(uio) > 0 && error == 0) {
        uio_update(uio, 0);

        switch (minor(dev)) {

            /*
             * minor device 0 is physical memory 
             */
        case 0:
#if defined(SECURE_KERNEL)
            return (ENODEV);
#else
            if (setup_kmem == 0)
                return (ENODEV);
#endif

            v = trunc_page(uio->uio_offset);
            if (uio->uio_offset >= (off_t) mem_size)
                goto fault;

            size = PAGE_SIZE;
            if (kmem_alloc(kernel_map, &where, size)
                != KERN_SUCCESS) {
                goto fault;
            }
            o = uio->uio_offset - v;
            c = min(PAGE_SIZE - o, uio_curriovlen(uio));
            error = uiomove((caddr_t) (where + o), c, uio);
            kmem_free(kernel_map, where, PAGE_SIZE);
            continue;

            /*
             * minor device 1 is kernel memory 
             */
        case 1:
#if defined(SECURE_KERNEL)
            return (ENODEV);
#else
            if (setup_kmem == 0)
                return (ENODEV);
#endif
            /*
             * Do some sanity checking 
             */
            if (((vm_address_t) uio->uio_offset >= VM_MAX_KERNEL_ADDRESS) || ((vm_address_t) uio->uio_offset <= VM_MIN_KERNEL_AND_KEXT_ADDRESS))
                goto fault;
            c = uio_curriovlen(uio);
            if (!kernacc(uio->uio_offset, c))
                goto fault;
            error = uiomove((caddr_t) (uintptr_t) uio->uio_offset, (int) c, uio);
            continue;

            /*
             * minor device 2 is EOF/RATHOLE 
             */
        case 2:
            if (rw == UIO_READ)
                return (0);
            c = uio_curriovlen(uio);
            break;
        case 3:
            if (devzerobuf == NULL) {
                MALLOC(devzerobuf, caddr_t, PAGE_SIZE, M_TEMP, M_WAITOK);
                bzero(devzerobuf, PAGE_SIZE);
            }
            if (uio->uio_rw == UIO_WRITE) {
                c = uio_curriovlen(uio);
                break;
            }
            c = min(uio_curriovlen(uio), PAGE_SIZE);
            error = uiomove(devzerobuf, (int) c, uio);
            continue;
        default:
            goto fault;
            break;
        }

        if (error)
            break;
        uio_update(uio, c);
    }
    return (error);
 fault:
    return (EFAULT);
}

boolean_t kernacc(off_t start, size_t len)
{
    off_t base;
    off_t end;

    base = trunc_page(start);
    end = start + len;

    while (base < end) {
        if (kvtophys((vm_offset_t) base) == 0ULL)
            return (FALSE);
        base += page_size;
    }

    return (TRUE);
}
